| The changes in manufacturing have been a challenge for industry.The requirements of high speed cutting,high efficiency cutting,dry cutting and energy saving and environment protection impulse people to study the wear reason.It was found that the wear mode of tool is abrasive wear,adhesive wear,fatigue wear and corrosion wear.To adapt to the change of material processing performance,high speed steel cutter,hard alloy cutter ceramic tool,ceramic-metal tool,diamond tool and PCBN cutter were researched.With gas deposition technology appeared,the cutting tool has a new development direction.Coating tool is a composite tool that deposits hard coating on the surface of tool.The coating can prolong the life of cutter and relieve the blade broken and crescent pits appear.PCBN cutting tools were widely used in automobile engineer which was suitable for finishing and semi-fishing.The wear mode of PCBN cutting tool is mechanical wear,oxidation wear,bond wear and chemical wear.After PCBN cutting tool was used,debris tumour,blade broken and crescent moon can be seen in tool surface.Due to above reasons,this project hopes to improve the cutting performance of PCBN tools by coating.The main research of this topic is:(1)The CrN coating was prepared by DC Magnetic Sputtering on the surface of PCBN,and the influence of current,temperature,nitrogen and argon flow ratio were studied.The surface morphology of CrN coating prepared in different temperatures was observed.The influence of process parameters on coating thickness and hardness was studied.Research shows that 1)when the flow ratio changes,the composition of the coating will change.2)Uniformity of the coating is improved when the temperature increases.3)The average friction coefficient of DC Magnetic Sputtering was 0.35.4)The growth rate of the coating changes when the current changes.5)The hardness of the CrN coating can be detected when the thickness is enough.6)The homogenization of coating prepared on RF is better than that of DC.7)The average friction coefficient of the coating prepared on RF was 0.25.(2)TiN coatings were prepared by DC Magnetic Sputtering and RF Magnetic Sputtering.The changes of current,temperature and the ratio of nitrogen and argon were studied,and the composition of the coating was studied.The surface morphologies of TiN coating prepared in different temperatures were observed.The influence of processing parameters on coating thickness and hardness was studied.Research shows that 1)when the flow ratio changes,the composition of coating will change.2)uniformity of the coating is improved when the temperature increases.3)The average friction coefficient of TiN coating in DC Magnetic Sputtering was 0.40.4)The growth rate of the coating will change when the current changes.5)The hardness of TiN coating can be detected,if thickness is enough.6)The homogenization of coating prepared in RF is better than that of DC.7)The average friction coefficient of the coating prepared in RF was 0.35.8)The friction coefficient of the coating was changed by doping Al in TiN coating ande the average friction coefficient of it is 0.3. |
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